Posts tagged neuroimaging
Articles and news from the latest research reports.
Meditation appears to produce enduring changes in emotional processing in the brain
A new study has found that participating in an 8-week meditation training program can have measurable effects on how the brain functions even when someone is not actively meditating. In their report in the November issue of Frontiers in Human Neuroscience, investigators at Massachusetts General Hospital (MGH), Boston University (BU), and several other research centers also found differences in those effects based on the specific type of meditation practiced.
"The two different types of meditation training our study participants completed yielded some differences in the response of the amygdala – a part of the brain known for decades to be important for emotion – to images with emotional content," says Gaëlle Desbordes, PhD, a research fellow at the Athinoula A. Martinos Center for Biomedical Imaging at MGH and at the BU Center for Computational Neuroscience and Neural Technology, corresponding author of the report. "This is the first time that meditation training has been shown to affect emotional processing in the brain outside of a meditative state."
Several previous studies have supported the hypothesis that meditation training improves practitioners’ emotional regulation. While neuroimaging studies have found that meditation training appeared to decrease activation of the amygdala – a structure at the base of the brain that is known to have a role in processing memory and emotion – those changes were only observed while study participants were meditating. The current study was designed to test the hypothesis that meditation training could also produce a generalized reduction in amygdala response to emotional stimuli, measurable by functional magnetic resonance imaging (fMRI).
Brain imaging alone cannot diagnose autism
In a column appearing in the current issue of the journal Nature, McLean Hospital biostatistician Nicholas Lange, ScD, cautions against heralding the use of brain imaging scans to diagnose autism and urges greater focus on conducting large, long-term multicenter studies to identify the biological basis of the disorder.
"Several studies in the past two years have claimed that brain scans can diagnose autism, but this assertion is deeply flawed," said Lange, an associate professor of Psychiatry and Biostatistics at Harvard Medical School. "To diagnose autism reliably, we need to better understand what goes awry in people with the disorder. Until its solid biological basis is found, any attempt to use brain imaging to diagnose autism will be futile."
While cautioning against current use of brain imaging as a diagnostic tool, he is a strong proponent of using this technology to help scientists better understand autism. Through the use of various brain imaging techniques, including functional magnetic resonance imaging (MRI), positron emission tomography (PET), and volumetric MRI, Lange points out that researchers have made important discoveries related to early brain enlargement in the disorder, how those with autism focus during social interaction and the role of serotonin in someone with autism.
"Brain scans have led to these extremely valuable advances, and, with each discovery, we are getting closer to solving the autism pathology puzzle," said Lange. "What individuals with autism and their parents urgently need is for us to carry out large-scale studies that lead us to find reliable, sensitive and specific biological markers of autism with high predictive value that allow clinicians to identify interventions that will improve the lives of people with the disorder."
Autism and autism spectrum disorder (ASD) are terms regularly used to describe a group of complex disorders of brain development. This spectrum characterized, in varying degrees, by difficulties in social interaction, verbal and nonverbal communication, and repetitive behaviors, whose criteria have been revised in the newly proposed Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The prevalence of ASD in the United States has increased 78 percent in the last decade, with the Centers for Disease Control estimating that one in 88 children has ASD.
(Source: eurekalert.org)
This is your brain on politics
With the U.S. presidential election just days away, new research from the University of South Carolina provides fresh evidence that choosing a candidate may depend more on our biological make-up than a careful analysis of issues.
That’s because the brains of self-identified Democrats and Republicans are hard-wired differently and may be naturally inclined to hold varying, if not opposing, perceptions and values. The USC study, which analyzed MRI scans of 24 USC students, builds on existing research in the emerging field of political neuroscience.
“The differences are significant and real,” said lead researcher Roger D. Newman-Norlund, an assistant professor of exercise science in the Arnold School of Public Health and the director of USC’s new Brain Simulation Laboratory.
The study focused on the mirror neuron system, a network of brain areas linked to a host of social and emotional abilities. After declaring their political affiliation, The subjects were given questionnaires designed to gauge their attitudes on a range of select political issues. Next, they were given “resting state” MRIs which made it possible to analyze the strength of connections within the mirror neuron system in both the left and right hemispheres of their brains; specifically the inferior frontal gyrus, supramarginal gyrus and angular gyrus.
The results found more neural activity in areas believed to be linked with broad social connectedness in Democrats (friends, the world at-large) and more activity in areas linked with tight social connectedness in the Republicans (family, country). In some ways the study confirms a stereotype about members of the two parties — Democrats tend to be more global and Republicans more America-centric — but it actually runs counter to other recent research indicating Democrats enjoyed a virtual lock on caring for others.
Speed-Learning a New Language May Help Brain Grow
Learning a new language over a short period of time appears to make the brain grow, new research suggests. The new study included young recruits at the Swedish Armed Forces Interpreter Academy who went from having no knowledge of a new language to speaking it fluently within 13 months. The recruits studied at a furious pace: from morning to evening, weekdays and weekends.
The recruits were compared to medicine and cognitive science students at a university (the “control” group), who also studied hard, but weren’t learning a new language. Both groups underwent MRI brain scans before and after a three-month period of intensive study. The scans showed that the brain structure of the control group remained unchanged, but certain parts of the brain of the language students grew.
This growth occurred in the hippocampus, a structure involved in learning new material and spatial navigation, and in three areas of the cerebral cortex. Among the recruits, those who took naturally to learning a new language had greater growth in the hippocampus and areas of the cerebral cortex related to language learning, while those who had to put more effort into learning a new language had greater growth in an area of the motor region of the cerebral cortex, the investigators found.
"We were surprised that different parts of the brain developed to different degrees depending on how well the students performed and how much effort they had had to put in to keep up with the course," Johan Martensson, a researcher in psychology at Lund University in Sweden, said in a university news release.
Martensson noted that previous research has indicated that bilingual and multilingual people develop Alzheimer’s disease at a later age. “Even if we cannot compare three months of intensive language study with a lifetime of being bilingual, there is a lot to suggest that learning languages is a good way to keep the brain in shape,” Martensson said.
The study appeared in the Oct. 15 issue of the journal NeuroImage.
Brainwave Training Boosts Network for Cognitive Control and Predicts Mind Wandering
A breakthrough study conducted in Canada has found that training of the well-known brainwave in humans, the alpha rhythm, enhances a brain network responsible for cognitive-control which correlates with reductions in mind-wandering. The training technique, termed neurofeedback, is being considered as a promising method for restoring brain function in mental disorders. Using several neuroimaging methods, a team of researchers working at the University of Western Ontario have now uncovered that functional changes within a key brain network occur directly after a 30-minute session of noninvasive, neural-based training. Dysfunction of this cognitive-control network has previously been implicated in a range of brain disorders including attentional deficit hyperactivity disorder, schizophrenia, depression and post-traumatic stress disorder.
How Does the Brain Process Art?
New imaging techniques are mapping the locations of our aesthetic response
In Michelangelo’s Expulsion from Paradise, a fresco panel on the ceiling of the Sistine Chapel, the fallen-from-grace Adam wards off a sword-wielding angel, his eyes averted from the blade and his wrist bent back defensively. It is a gesture both wretched and beautiful. But what is it that triggers the viewer’s aesthetic response—the sense that we’re right there with him, fending off blows?
Recently, neuroscientists and an art historian asked ten subjects to examine the wrist detail from the painting, and—using a technique called transcranial magnetic stimulation (TMS)—monitored what happened in their brains. The researchers found that the image excited areas in the primary motor cortex that controlled the observers’ own wrists.
“Just the sight of the raised wrist causes an activation of the muscle,” reports David Freedberg, the Columbia University art history professor involved in the study. This connection explains why, for instance, viewers of Degas’ ballerinas sometimes report that they experience the sensation of dancing—the brain mirrors actions depicted on the canvas.
Freedberg’s study is part of the new but growing field of neuroaesthetics, which explores how the brain processes a work of art. The discipline emerged 12 years ago with publication of British neuroscientist Semir Zeki’s book, Inner Vision: An Exploration of Art and the Brain. Today, related studies depend on increasingly sophisticated brain-imaging techniques, including TMS and functional magnetic resonance imaging (fMRI), which maps blood flow and oxygenation in the brain. Scientists might monitor an observer’s reaction to a classical sculpture, then warp the sculpture’s body proportions and observe how the viewer’s response changes. Or they might probe what occurs when the brain contemplates a Chinese landscape painting versus an image of a simple, repetitive task.
Ulrich Kirk, a neuroscientist at the Virginia Tech Carilion Research Institute, is also interested in artworks’ contexts. Would a viewer respond the same way to a masterpiece enshrined in the Louvre if he beheld the same work displayed in a less exalted setting, such as a garage sale? In one experiment, Kirk showed subjects a series ofimages—some, he explained, were fine artwork; others were created by Photoshop. In reality, none were Photoshop-generated; Kirk found that different areas of viewers’ brains fired up when he declared an image to be “art.”
Kirk also hopes one day to plumb the brains of artists themselves. “You might be able to image creativity as it happens, by putting known artists in the fMRI,” he says.
Others, neuroscientists included, worry that neuroscience offers a reductionist perspective. Vilayanur Ramachandran, a neuroscientist at the University of California at San Diego, says that neuroaesthetics undoubtedly “enriches our understanding of human aesthetic experience.” However, he adds, “We have barely scratched the surface…the quintessence of art, and of genius, still eludes us—and may elude us forever.”
(Source: smithsonianmag.com)
The Neuroscience Of Music
Why does music make us feel? On the one hand, music is a purely abstract art form, devoid of language or explicit ideas. The stories it tells are all subtlety and subtext. And yet, even though music says little, it still manages to touch us deep, to tickle some universal nerves. When listening to our favorite songs, our body betrays all the symptoms of emotional arousal. The pupils in our eyes dilate, our pulse and blood pressure rise, the electrical conductance of our skin is lowered, and the cerebellum, a brain region associated with bodily movement, becomes strangely active. Blood is even re-directed to the muscles in our legs. (Some speculate that this is why we begin tapping our feet.) In other words, sound stirs us at our biological roots. As Schopenhauer wrote, “It is we ourselves who are tortured by the strings.”
We can now begin to understand where these feelings come from, why a mass of vibrating air hurtling through space can trigger such intense states of excitement. A paper in Nature Neuroscience by a team of Montreal researchers marks an important step in revealing the precise underpinnings of “the potent pleasurable stimulus” that is music. Although the study involves plenty of fancy technology, including fMRI and ligand-based positron emission tomography (PET) scanning, the experiment itself was rather straightforward. After screening 217 individuals who responded to advertisements requesting people that experience “chills to instrumental music,” the scientists narrowed down the subject pool to ten. (These were the lucky few who most reliably got chills.) The scientists then asked the subjects to bring in their playlist of favorite songs – virtually every genre was represented, from techno to tango – and played them the music while their brain activity was monitored.
Scientists read dreams: Brain scans during sleep can decode visual content of dreams
A team of researchers led by Yukiyasu Kamitani of the ATR Computational Neuroscience Laboratories in Kyoto, Japan, used functional neuroimaging to scan the brains of three people as they slept, simultaneously recording their brain waves using electroencephalography (EEG).
The researchers woke the participants whenever they detected the pattern of brain waves associated with sleep onset, asked them what they had just dreamed about, and then asked them to go back to sleep.
This was done in three-hour blocks, and repeated between seven and ten times, on different days, for each participant. During each block, participants were woken up ten times per hour. Each volunteer reported having visual dreams six or seven times every hour, giving the researchers a total of around 200 dream reports.
'Google of the brain' neuroimaging project receives $2.5 million NIH grant
Indiana University Bloomington cognitive scientist Michael Jones, in collaboration with researchers at the University of Colorado, University of Texas at Austin and Washington University in St. Louis, was awarded $2.5 million from the National Institute of Mental Health to develop an automated system for large-scale synthesis of human neuroimaging data.
The four-year award will support the development of NeuroSynth.org, an online platform that is intended to be sort of a “Google of the brain” for researchers in cognitive neuroscience. The unique system will be designed to learn new concepts, draw inferences and make discoveries based on the collected sources.
"There is a vast amount of so-called ‘unrealized knowledge’ across a number of scientific sources — yet-to-be discovered information that is not located in any specific article, but is rather distributed across many," Jones said. "Scientists are regularly reading distinct but related articles to make these discoveries, and NeuroSynth will attempt to simulate and scale up this knowledge discovery process, generating novel hypotheses to test with future experiments."